Internal-combustion engine.



A. P. suoi-Tv. l INTERNAL GOMBUSTION ENGINE.

APPLIOATION FILED 13120.30, 1905. 1 y

Patented Aug. 23, 1910.

lf/ESSS: MMM/hm ARTHUR romans scoTT, or BRADFORD, ENGLAND.

INTEBAL-COMBUSTION ENGINE.

Specification of Letters Patent.

Patented Aug; 23, 1910.

ApplicationV led IJeeember 3Q, 1905. Serial No. 294,031.

To all whom it may concern.

Be 4it known that I, ARTHUR FORBES SCOTT, M. I. Mech. E., a subject of the King of England, residing at 171 SwanvArcade,

Bradford, England, have invented certain new and useful Improvements in Internal- Conibustion Engines, of which the following is a specification.r

This invention relates chiefly to limprovements in two stroke cycle internal combustion engines in which the exhaust is controlled by the piston, and its main objectis to provide an engine working with'l gas or an explosive mixture so that a scavengingt charge of air 1s admitted before the explosive charge enters.

The accompanying drawingis a section of one cylinder of a vertical engine and its parts constructed in accordance with my improvements. v

The motor cylinder' A' has an extension C below of larger diameter and is fitted with a piston of two diameters D and B, the part of larger diameter B having its 'underside preferably open to the crank chamber M and acting as a pump, while the upper trunk part D is the motor piston. The lower part of the motor cylinder A is `provided with exhaust ports E and ports O which are preferably, as shown in the drawing, on the opposite side and which areconnected with the crank chamber'M or bottom of the cylinder C by means of a separating pipe or passage T, which preferably has a spiral course as shown so as to obtain a desirable length of passage with 'compactness The motor and pump ,cylinders A. and C contain "respec' tively air and gas mixture inlet ports K and L and the motor piston D is provided 'with a deector D3 on the top andhas a recess J in its side, and the-whole is arranged sol that when the pistonwhich is connected to the .balanced crank N approaches the top of the stroke the recessed port J therein connects (as shown in the drawing) the air inlet K with the-port O leading into the top of the separating passage T, and at the same time' the pump part B of the piston uncovers the gas inlet L to the crank chamber M, and the partial vacuum in the latter causes the scavenging and explosive charges to simultaneously enter the separating passage T and crank chamber M respectively, the proportions of the two charges being dependent ou size or opening of the two inlets or admitting ports K (or C) and L. The scavenging air 'is thus held in the separatingy passage T, and when the piston approaches' the bottom of the stroke and has opened the exhaust E the air enters the cylinder `by the ports O'and is followed by thegas mixture, when compression and ignition take place in the usual manner.

On account of the pre-admission of air to the cylinder a small rich explosive charge may be used and the admission of same being delayed this distribution tends to prevent any loss at the exhaust ports, and also to avert danger of explosion inthe crank chamber when the piston uncovers the ports O, owing to the interposingv column of air 'in the long passage T. The scavenging air besideshaving a cooling effect tends to raise the mean pressure in the cylinder and to er1- able the engine to run with greater range of load', and so frees it from the chief disadvantages of the ordinary non-scavenging two stroke cycle engine, in which the volume of burned gases before ignition sometimes exceeds the volume Iof gasniixture which has been admitted.

By suitably proportioning thegas and air inlets or admitting ports and the amount` of opening of same; the dimensions of piston; and other parts; the required amounts of gaseous and scavenging charges are obtained and the lengthened course of the separating passage prevents much admixture of the two charges;

The engine may be regulated by governing either of the passages, the separating passage being made large enough to hold the scavenging charge. Throttling the gas mixture at L will increase the amount of air entering at K- unles's K is also throttled-and vice versa.

A valveless internal combustion engine comprising a motor cylinder and a pum cylinder of diferent diameters, the latter being of greater capacity than the former, a piston of two diameters, the smaller part working in the motor cylinder and the larger'part in the pump cylinder, a crank chamber connected to the pump cylinder, a long separat-ing passage o suficient capacity for retaining the whole of the scavenging charge of air and leading from the motor cylinder to the crank chamber, an air inlet port leading from', the atmosphere directly through the motor cylinder, exhaust and gas inlet ports, a recess or port in the motor part of the piston, which recess, at the top of the stroke, runs over and connects the air in1et port and the motor cylinder admission port which leads into one end of the separating passa e, While at the same time the pump part o the piston connects the said crank chamber with the gas inlet port by rising above the latter, the air entering the separating passage only, While 10 the gas enters the crank chamber, so that when the charge of air in the separating passage enters the cylinder it precedes the gas charge from the crank chamber.`

In Witness whereof I have hereunto set my hand in presence of two Witnesses.

l ARTHUR FORBES SCOTT.

Witnesses: l

CEGIL A. S. BAXTER, DAVID NOWELL. 

